Lightweight Design And Optimization For Al-Structured Frontal Auto-Subframe

Lightweight design for pure electric vehicles can not only improves the steering stability of the car,shortens the braking distance,but also improves the active safety.It can reduce the energy consumption,install larger capacity batteries under the same overall quality,and extend the driving distance.The frontal auto-subframe of the car is an important part of the chassis of the car,which has a great impact on the comfort,handling and durability of the car.It is an important basis for measuring the level of chassis design.It is of great significance and practical value to apply aluminum alloy material and reasonable structural design and optimization to the frontal auto-subframe to realize the lightweight design of the frontal auto-subframe.Combine with the lightweight development of the aluminum alloy frontal auto-subframe of a pure electric vehicle of a certain enterprise,this paper discusses the lightweight design method of the aluminum alloy frontal auto-subframe.On the basis of summarizing the existing development practices,a lightweight design method for the aluminum alloy frontal autosubframe is explored.Under the guidance of this method,the aluminum alloy frontal autosubframe is analyzed and optimized,and the development of the aluminum alloy frontal autosubframe is completed.The feasibility of the design method is verified and good lightweight effect is achieved.Firstly,based on the modern design method,a lightweight design process which is suitable for the structure of aluminium alloy frontal auto-subframe is proposed,and the aluminium alloy frontal auto-subframe is developed based on this process.On the basis of obtaining the original version CAD model of the product,the finite element model of the aluminum alloy frontal autosubframe is established.The validity of the finite element model is verified by the comparison between free modal simulation and modal test.Furthermore,the multi-performance detailed analysis of the frontal auto-subframe is carried out,and the analysis model of the strength,stiffness and fatigue life of the frontal auto-subframe is established respectively,and the performance index of the frontal auto-subframe is obtained.The analysis results show that the frontal auto-subframe of the original version design is conservative,and the performance margin is large.So there is potential for further optimization for the frontal auto-subframe.Then,the multi-performance comprehensive optimization of anti-fatigue and lightweight of the frontal auto-subframe is carried out.The structure of the frontal auto-subframe is analyzed,and the design variables for structural optimization are defined.The frontal autosubframe is optimized by combining the response surface method and the optimization strategy of multi-objective genetic algorithm.And then the design scheme under deterministic optimization is obtained.After updating the calculation model of strength,stiffness,modality and fatigue,the performance before and after optimization is compared.On the basis of meeting the performance constraints,this method improves the design efficiency and reduces the weight by more than 40% compared with the steel frontal auto-subframe.In addition,this paper combines Monte Carlo simulation method,6? quality design,approximate model technology and sequence optimization method based on reliability evaluation to carry out 6? reliability optimization design of aluminium alloy auto-subframe,which improves the reliability and robustness of aluminium alloy frontal auto-subframe products.The lightweight design method proposed in this paper has a certain reference significance for the design and development of auto-subframe and other structures in the future.